Factors / Factors of 255

Factors of 255

1, 3, 5, 15, 17, 51, 85, 255

255 breaks into 4 pairs, tested up to √255 ≈ 16.0; each pair multiplies back to 255 exactly. 255's full pair list is (1, 255), (3, 85), (5, 51), (15, 17), for 8 divisors in total. 255's divisors other than 255 itself sum to just 177, 78 below 255: the common deficient case. 255 is odd, digit sum 12 for 255; small divisors of 255 include 3, 5. 255 has 8 divisors; 254 has 4 and 256 has 9, so 256 wins here. 255 divided by its largest divisor, 85, gives 3.